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E N T O M 
4 han to tlie claffes above them. Many are attached to 
one vegetable, Come to a (ingle leaf, where the period of 
their lives is completed in a fevv weeks, or perhaps a few 
days or hours ; and where the pleafures they enjoyed, or 
the purpofes for which they were produced, are in a great 
meafure beyond the reach of our faculties to explore. 
Of the PARTIS of INSECTS. 
An infedl is denned to be, an animated being deditufe 
of bones; but which, inftead thereof, is covered with a 
very hard (kin which fupplies the place of edification ; 
has fix or more feet; and breathes through fpiracula, or 
pores placed in the fide of the body : yet infedls are very 
diltindt from, and mud not be confounded with, verm* or 
worms. Quadrupeds, birds, and fillies, have all an inter- 
jnal fkeleton of bones, to which the mufcles are affixed ; 
but the whole interior of infedls is compofed of f'oft flefh, 
and the mufcles are attached to an external (hell, which 
ierves the double purpofe of (kin and bone, completely 
exemplified in the crab and lobftcr.—See the article Can¬ 
cer, vol.iii. p. 704 — 707. 
Infedls are divided into four principal parts : the caput , 
or head; the thorax , or trunk; the abdomen , or belly; 
thearfar, or limbs. The Head is affixed to the thorax 
by a fpecies of articulation or joint; it is the principal 
feat of the fenfes, and, ^s proved by Fabricius, contains 
the rudiments of the brain ; it is furniihed with a mouth, 
eyes, antennae, a forehead, a throat, and ftemmata. In 
the greater part of infedls the heafl is didindtly divided 
from the thorax, but in others it coalefces with it. The 
head of fome infedls is very large compared with the fize 
of their bodies ; the proportion between the head of the 
fame infedl is not always fimilar ; in the caterpillars with 
horny heads it is generally fmall, before they moult or 
change their fk in, but much larger-after each moulting. 
The hardnefs of the exterior part of the head prevents its 
growth before the change ; it is, confequently, in propor¬ 
tion to the body very fmall; but when the infedl is dif- 
pofing itfelf for the change, the internal fubftance of the 
head retires inwards to the firft ring of the neck, where it 
has room to expand itfelf; fo that when the animal quits 
the (kin, we are furprifed with a head twice the former 
fize ; and, as the infedl neither eats nor grows while the 
head is forming, there is this further circumftance to be 
remarked, that the body and the head have each their 
particular time of growth : while the head expands and 
grows, the body does not grow at all ; when the body 
increafes, the head remains of the fame fize, without any 
change. 
Os, the mouth, is a part of the infedl to which entomo- 
logids will find it rieceffary to pay a very particular atten¬ 
tion. Fabricius goes fo far as to affiert that, without a 
thorough knowledge of the mouth, its form, and various 
appendages, it will be impofiible to diferiminate with ac¬ 
curacy one infedl from another. In the ftrudture of the 
mouth confiderable art and wifdoin is difplayed; the di- 
verfity of the figure is almoft as great as the variety of 
fpecies. It is tifually placed in the forepart of the head, 
extending fomewhat downwards : in the chermes, coccus, 
and fome other infedls, it is placed under the bread. In 
fome infedls, the mouth is forcipated, to catch, hold, and 
tear, the prey; in others, aculeated, to pierce and wound 
animals, and f uck their blood ; in others, drongly ridged 
jaws and teeth, to gnaw and ferape out their food, carry 
burdens, perforate the earth, nay the harded wood, and 
even dones, for habitations and neds for their young. 
Others are furnidied with a kind of tube, at one time 
moveable, at another fixed, with which they fuck the 
jnices of the flowers. 
Maxilla , the jaws, are generally two in number ; in 
fome, four ; in others, more. They are fometimes placed 
in an horizontal, fometimes in a tranfverfc, diredlion; 
the inner edge is ferrated, or furniihed with fmall teeth, 
as in the cicada, nepa, notonedla, cimex, aphis^ and re. 
O L O G Y. 
markably fo in fome curculeones. They move the jaws 
from right to left, not up and down, but fideways. 
The roftnun, or probofeis, is a very curious and compli¬ 
cated organ ; it is t he mouth drawn out to a rigid point. 
In many infedls of the hemiptera clafs, it is bent down 
towards the bread and belly. It has by fome writers 
been confidered as ferving at once the different purpofes 
of month, nofe, and windpipe, enabling the infedl to ex- 
tradl the juices of plants, communicate the fenfation of 
fmelling, and convey air to the body. 
Lingua, the tongue, is a taperand compadl inftrument, 
by which the infedl obtains the juices of plants. Some 
can contract or expand it, others roll it up with dex¬ 
terity ; in fome it isinclo(ed within a (heath. It is taper 
and fpiral in the butterfly, tubular and fi'efiiy in the fly ; 
in all affording under the microfcope, a mod lingular dif- 
play of curious ntechanifm. Swammerdam, when fpeak- 
ing of the probofeis of the butterfly, is full of admiration ; 
“ I cannot refrain, (fays he,) from confelling to the glory 
of the Immenfe and Incomprehenfible Architedl, that I 
have but impetfedlly deferibed and reprefented this fmall 
organ ; for, to represent it to the life in its full perfedlion, 
as truly mod perfedl it is, far exceeds the utmod efforts 
of human knowledge.” Reaumur breaks out into fimilar 
expreflions, on describing the probofeis of the bee, with 
which they take their nourifitment, and colledl the honey. 
See thisindrumentdeferibedandfigured under Apis, vol .i. 
p. 796. The probofeis of the bee is ffiaped like a barbed 
javelin, but that of the butterfly is a fpiral fubdance, 
fomewhat refentbling the fpring of a watch when wound 
up ; as may be feen in the butterfly, in the Entomology 
Plate I. fig. 6. By means of a pin it can be gently pulled 
out to its full length ; it grows gradually tapering from 
the bafe, at the end it divides or feparates into two tubes, 
each furnidied with little organs of fudtion ; probably, it 
is by thefe that it exrradls the juices on which it feeds, 
and not by the extreme ends of the tongue. As the but¬ 
terfly has no mouth, the probofeis is the only alimentary 
organ ; when feparated from the infedl, it will often un¬ 
roll itfelf, then wind and coil itfelf up again, continuing 
thele motions at intervals for a confiderable time. 
The probofeis of the tabanus, or ox fly, is alfo of a very 
Angular and curious drudlure. The whole apparatus is 
compofed of fix parts, exclufive of the two guards or 
feelers, all of which are inclofed in a fleflty cafe, which 
opens at the will of the animal, and lets out its weapon, 
whenever difpofed to pierce the hides of cattle, and fuck 
their blood. But the mod Angular and curious confor¬ 
mation of a probofeis, if it may be fo called, is the inflated 
projection of the head of the lanthorn-fly, which, in lu¬ 
minous fplendour, fo far exceeds the refulgence of the 
glow-worm, as to enable the inhabitants of South Ame¬ 
rica to read by its light, and travellers are even faid to be 
directed on their journey, by fixing one or two.of them to 
the end of a ftick. See their natural hifiory, and an en¬ 
graving of them, under Fulgora, vol. vii. 
Antennae. —Thefe are fine fiender horns, confiding of 
feveral articulations, moveable in various directions, and 
conflituting one of the diferiminating charadleriftics of 
infects. They are beautiful in form, and of a very deli¬ 
cate ftrudture, fo finely articulated, and fo minutely joint¬ 
ed, as to be indantaneoufly moveable in every diredlion. 
They are fituated on the fore part of the head. The 
fhape, the length, the number, and kind of articulations, 
not only vary in different fpecies, but the antennae of the 
male generally differ from thofe of the female. The 
greater number of infedls have only two antennae, but 
the onifeus, the pagurus, and adacus, have four. Re. 
gular rows of minute holes are obfervable in the antennae, 
which are fuppofed to be nafal apertures, poffelfing the 
faculty of feent. Several infedls cover their eyes with 
the antennae, while they deep. But we are far from being 
certain of the pofitive ufe of this indrument: fome writers 
have merely conjedtured that they are the organs of fmell 
